Security researchers used Claude to hack into OpenAI and got paid for it

Turns out AI chatbots are getting really good at breaking into things, and OpenAI just found out the hard way. A new Wall Street Journal report reveals that a small team of security researchers used Anthropic’s Claude to hack an OpenAI employee’s ChatGPT account. Once inside, they got access to the company’s private codebase.

The researchers, who go by Hacktron AI, were working through OpenAI’s bug bounty program, which lets outside researchers legally attack a company’s systems without getting into trouble for it. As soon as they realized what they had access to, they flagged it to OpenAI, which paid the team $6,500 for the find.

How did the hack actually happen?

It all traces back to a flaw the team spotted in Discourse, the outside platform that powers OpenAI’s community forum. They had Claude generate exploit code to take advantage of the bug, and at first, the attempt fell flat. Then Anthropic rolled out Opus 5, and the very next day, Claude had cracked it.

That exploit opened the door to authentication tokens sitting on the Discourse server. Oddly enough, some of those tokens also worked on ChatGPT itself, and a few belonged to actual OpenAI staffers. From there, the access stretched all the way to OpenAI’s GitHub, letting the team browse files inside a repository called Monorepo, said to house a lot of OpenAI’s technical know-how, though not the actual model weights.

To leave proof they had gotten this far, the researchers submitted a small pull request tagging their team’s name. OpenAI never approved it, but the message landed anyway.

What does this mean for AI security going forward?

OpenAI confirmed that both security gaps are now closed, and Discourse pushed out its fix the same day it got word of the issue. But here’s the part that should give everyone pause: this entire breach came from three researchers armed with nothing more than regular Claude and Codex subscriptions.

If that’s what a small independent team can do, it’s worth wondering what well-funded, nation-backed hacking groups have already become capable of. AI is quietly handing serious hacking skills to people who never needed to earn them the hard way, and there is no putting that back in the bottle.